Cyber Resilience

CVE-2025-12734

Gitlab 15.6.0 – 18.4.6

Published
11 December 2025
Modified
23 December 2025
Patch / advisory
View advisory
CVSS Score v3.1 3.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
EPSS Score 0.0023 14th percentile
Risk Priority 15 floored blend · peak EPSS

Summary

CVE-2025-12734 is a low-severity Improper Encoding or Escaping of Output (CWE-116) vulnerability in Gitlab Gitlab. Its CVSS base score is 3.5 (Low).

Operationally, ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-15 (Information Output Filtering) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A05:2025 Injection

EU & UK References

Vulnerability Data

GitLab has remediated an issue in GitLab CE/EE affecting all versions from 15.6 before 18.4.6, 18.5 before 18.5.4, and 18.6 before 18.6.2 that could have allowed an authenticated user to, under certain conditions, render content in dialogs to other users…

more

by injecting malicious HTML content into merge request titles.

CWE(s)
CWE-116

Related Threats

CVEs Like This One

CVE-2024-6329Same product: Gitlab Gitlab
CVE-2025-8405Same product: Gitlab Gitlab
CVE-2025-12697Same product: Gitlab Gitlab
CVE-2023-2200Same product: Gitlab Gitlab
CVE-2024-4099Same product: Gitlab Gitlab
CVE-2023-2030Same product: Gitlab Gitlab
CVE-2026-13151Same product: Gitlab Gitlab
CVE-2024-1211Same product: Gitlab Gitlab
CVE-2023-5009Same product: Gitlab Gitlab
CVE-2023-0632Same product: Gitlab Gitlab

Affected Assets

gitlab
gitlab
15.6.0 — 18.4.6 · 15.6.0 — 18.4.6 · 18.5.0 — 18.5.4

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-15 Information Output Filtering
  • SI-10 Information Input Validation
Detect
Catch it (NIST detect / respond)
  • SI-7 Software, Firmware, and Information Integrity
Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V1.1.2
  • V1.2.1
  • V1.2.3

Mitigating Controls (NIST 800-53 r5) AI

SI-15 Information Output Filtering good match
prevent

Directly requires filtering of information outputs to block unauthorized or malicious content such as injected HTML from being rendered to users.

SI-10 Information Input Validation good match
prevent

Requires validation and sanitization of all inputs (merge request titles) to reject or neutralize malicious HTML before storage or display.

SI-7 Software, Firmware, and Information Integrity partial match
detect

Provides integrity checks that can detect unauthorized or malformed content introduced via the merge-request title field.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require proper output encoding to prevent injection and message malformation.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.28 Secure coding mostly match
prevents

Secure coding standards explicitly require correct output encoding and escaping to preserve message structure.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing can detect missing or incorrect encoding but does not itself implement the control.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle mandates output encoding/escaping practices that directly prevent improper encoding.

A.8.26 Application security requirements partial match
prevents

Application security requirements include explicit rules for safe output handling and encoding.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure architecture principles reduce the likelihood of missing encoding but do not prescribe the actual technique.

References